Altered boundaries, retirements and the new 'top two' primary system make the state's House races more competitive and more expensive — at least $1 million per candidate in 11 cases.

WASHINGTON — California congressional races rarely drew the big bucks that more competitive races in other states did — after all, only one seat in the state had flipped between the parties in the last decade — but that was before new district boundaries shook up the political status quo.

Now, the Sacramento-area race between Republican Rep. Dan Lungren and Democrat Ami Bera has drawn more spending by outside groups than any congressional race in the country — more than $6.2 million — as the parties battle for control of the House.

In the San Fernando Valley, Democratic colleagues-turned-bitter-rivals Howard L. Berman and Brad Sherman have, along with outside groups, spent more than $11 million on the race, one of the nation's costliest.

Bill Bloomfield, a wealthy Manhattan Beach businessman running as an independent against Democratic Rep. Henry A. Waxman of Beverly Hills, has put more than $3.7 million of his own money into his campaign. Waxman, who has raised about $1.4 million, had more than $1 million in the bank as of Sept. 30 for the crucial final weeks of the campaign, according to the latest campaign finance reports.

In 11 of the state's 53 congressional districts, each of the candidates had raised more than $1 million, according to the Center for Responsive Politics, which tracks money in politics. That's up from the five races in 2010 in which opposing candidates each raised $1 million or more.

The big spending comes after a voter-approved citizens' commission drew a new political map, and after a spate of retirements by California House members.

As a result, the parties this year have targeted 10 of the state's congressional races, The House GOP campaign arm plans to spend about $10 million in California, more than ever before, a spokesman said. Its Democratic counterpart expects to spend $8.6 million, much of that for TV ads, a spokeswoman said.

The Central Valley race between Republican Rep. Jeff Denham and Democrat Jose Hernandez and the La Jolla-area battle between Republican Rep. Brian P. Bilbray and Democrat Scott Peters are among the top races in the country for independent spending by outside groups. Each has drawn more than $5 million.

The Stockton-area race between Democratic Rep. Jerry McNerney and Republican Ricky Gill also has drawn $2.5 million in outside spending, in addition to the more than $2 million each of the candidates has raised.

In addition, the state's new "top two" primary system that took effect this year set up a number of clashes between members of the same party.

The Berman-Sherman slugfest could come close to, perhaps even surpass, the $11.5-million spending record for a California House race set in 2000 in the Burbank-Glendale-area race won by Democrat Adam B. Schiff over Republican incumbent James E. Rogan.

Spirit of Democracy America, a "super PAC" heavily funded by Republican donor Charles Munger Jr., has spent $556,000 in support of Assemblyman Paul Cook of Yucca Valley in a congressional race against fellow Republican Gregg Imus, a tea partyer and founding member of an anti-illegal-immigrant border patrol group.

That's more than the candidates combined had spent, according to the Sunlight Foundation, a nonpartisan group that promotes transparency in government.